MSJC Automotive Technology

T. Wenzel

Hybridcars.com

P O R S C H E Cayenne Hybrid• Drive wheels: all

• Engine: 3.0-liter V6 with electric motor and battery pack

• Horsepower: 369 combined net (CG estimate)

• Torque: 406 lb-ft peak (CG estimate)

• Transmission: 8-speed automatic

Hybrids can provide performance while improving corporate fuel economy ratings.

Hybrid Cars Have Expensive Technology That is Difficult to Fix

• Hybrid cars are not unlike any modern computer-controlled vehicle. Like their conventional gasoline powered counterparts, they require high-end diagnostic equipment which is typically available at the dealerships.

• Hybrids cars have long warranties to protect consumers from high costs.

Source: The Essential Hybrid Car Handbook, by Nick Yost

Hybrid Cars Have Limited Battery Pack Life

• Hybrid cars are designed so that batteries are never fully charged or discharged.

• Manufacturers guarantee batteries for many years; ranging from eight years or 80,000 to 100,000 miles.

Source: The Essential Hybrid Car Handbook, by Nick Yost

Hybrid Cars Stall, Stutter and Sputter.

• Concern started with a Toyota Prius software problem in 2005, which shut-off vehicles while driving. This has been addressed through a recall.

Source: The Essential Hybrid Car Handbook, by Nick Yost

Hybrid Cars Will Not Return Enough Savings in Reduced Fuel Usage to Justify Their Higher Cost.

• Hybrid cars are hard to justify solely on fuel savings. They have higher depreciation and higher initial cost.

• Federal and state tax write-offs help, but are generally not enough to fully offset the cost.

• The amount and type of driving you do can have a great impact on fuel savings.

Source: The Essential Hybrid Car Handbook, by Nick Yost

Hybrid Cars Are Lower Performing

• Hybrid cars can safely accelerate and brake.

• Some are faster then their gasoline powered counterparts.

Source: The Essential Hybrid Car Handbook, by Nick Yost

Hybrid Cars Do Not Get the Fuel Mileage Promised

• What cars do get the fuel mileage promised?

• Most real-world driving situations yield about 15% lower fuel mileage than promised.

Source: The Essential Hybrid Car Handbook, by Nick Yost

Hybrid Vehicle Technology

Full Hybrid

• Runs on just gasoline, just electricity, or both.

• Toyota technology (used on Ford as well)

• Best in city driving.

• Example: Toyota Prius and Ford hybrids.

Assist Hybrid

• Electricity does not typically power the car by itself.

• Small gasoline engine gets “boost” from electric motor.

• Example: Honda Integrated Motor Assist (IMA)

Mild Hybrid

• Electric motor does not propel vehicle.

• Motor-generator replaces starter and alternator, allowing engine to shut-down and restart in traffic while running A/C.

• Example: GM pick-ups.

• In a series hybrid, the engine drives generator; the generator drives an electric motor.

• The gasoline engine is designed to run efficiently in its optimum efficiency range.

Toyota HybridsSource: Toyota Motor Company

• In a parallel hybrid, both engine power and electric power drive wheels.

• Battery is charged by causing the electric motor to act as a generator.

• The parallel hybrid system cannot drive the wheels from the electric motor while simultaneously charging the battery since the system has only one motor.

• A series/parallel hybrid combines the series hybrid system with the parallel hybrid system in order to maximize the benefits of both systems.

Planetary Gear

• It has two motors, and depending on the driving conditions, uses only the electric motor or the driving power from both the electric motor and the engine, in order to achieve the highest efficiency level.

• When necessary, the system drives the wheels while simultaneously generating electricity using a generator.

• This is the system used in the Prius.

1) ENERGY-LOSS REDUCTION

The system automatically stops the idling of the engine (idling stop), thus reducing the energy that would normally be wasted.

2) ENERGY RECOVERY AND REUSE

The energy that would normally be wasted as heat during deceleration and braking is recovered as electrical energy, which is then used to power the starter and the electric motor.

3) MOTOR ASSIST

The electric motor assists the engine during acceleration.

4) HIGH-EFFICIENCY OPERATION CONTROL

The system maximizes the vehicle’s overall efficiency by using the electric motor to run the vehicle under operating conditions in which the engine’s efficiency is low and by generating electricity under operating conditions in which the engine’s efficiency is high.

The series/parallel hybrid system has all of these characteristics and therefore provides both superior fuel efficiency and driving performance.

• High-efficiency gasoline engine that utilizes the Atkinson Cycle, which is a high-expansion ratio cycle.

• This allows pressure in the combustion chamber at the end of the power-stroke to be equal to atmospheric pressure.

• This uses all energy obtained from combustion process.

Atkinson Cycle

• Permanent magnet AC synchronous motor

• High-performance nickel-metal hydride (Ni-MH) battery

• Power control unit contains a high-voltage power circuit for raising the voltage of the power supply system for the motor and the generator to a high voltage of 500 V.

• AC-DC inverter for converting between the AC current from the motor and the generator and the DC current from the hybrid battery

• Power split device, which transmits the mechanical motive forces from the engine, the motor and the generator by allocating and combining them.

1 Start and low to mid-range speeds

• The engine stops when in an inefficient range, such as at start-up and in low to mid-range speeds.

• The vehicle runs on the motor alone. (A)

2 Driving under normal conditions

• Engine power is divided by the power split device.

• Some of the power turns the generator, which in turn drives the motor. (B)

• The rest of the power drives the wheels directly. (C)

• Power allocation is controlled to maximize efficiency.

3 Sudden acceleration

Extra power is supplied from the battery (A), while the engine and high-output motor provide smooth response (B+C) for improved acceleration characteristics.

4 Deceleration, braking

• The high-output motor acts as a high-output generator, driven by the vehicle’s wheels.

• This regenerative braking system recovers kinetic energy as electrical energy, which is stored in the high-performance battery. (D)

5 Battery recharging

• Battery level is managed to maintain sufficient reserves.

• The engine drives the generator to recharge the battery when necessary. (E)

• THS II uses an AC synchronous-type motor, which is a high-efficiency DC brushless motor with AC current.

• Neodymium magnets (permanent magnets) and a rotor made of stacked electromagnetic steel plates form a high-performance motor.

• The generator is also an AC synchronous type.

• In order to supply sufficient power to the high-output motor, the generator is rotated at high speeds, increasing its output.

• Runs up to 10,000 rpm. This high rpm has significantly increased the power supply up to the medium-speed range, improving the acceleration performance.

• The power control unit contains an inverter that converts the DC from the battery into an AC for driving the motor and a DC/DC converter for conversion to 12V.

• To maintain a constant charge, the new battery is discharged or receives charging energy from the generator and the motor.

• It does not require external charging, as do electric vehicles.

• A regenerative braking system is used which, during engine braking and braking using the foot brake, operates the electric motor as a generator, converting the vehicle’s kinetic energy into electrical energy, which is used to charge the battery.

• The system is particularly effective in recovering energy during city driving, where driving patterns of repeated acceleration and deceleration are common.

• When the footbrake is being used, the system controls the coordination between the hydraulic brake of the ECB and the regenerative brake and preferentially uses the regenerative brake, thereby recovering energy even at lower vehicle speeds.

ECB – Electronically Controlled Brake

• The hybrid transmission consists of the power split device, the generator, the electric motor and the reduction gears, etc.

• The power from the engine is split into two by the power split device. One of the output shafts is connected to the motor and the wheels while the other is connected to the generator.

• Power from the engine is transmitted through two routes, i.e., a mechanical route and an electrical route.

• The power split device uses a planetary gear.

• The rotational shaft of the planetary carrier inside the gear mechanism is directly linked to the engine

• It transmits the motive power to the outer ring gear and the inner sun gear via pinion gears.

• The rotational shaft of the ring gear is directly linked to the motor and transmits the drive force to the wheels, while the rotational shaft of the sun gear is directly linked to the generator.

Gasoline Engine

Motor/Generator

Battery

Electronics

Transmission - CVT or 5 speed

Mechanical Connections

Electrical Connections

Inside the Honda IMA Hybrid System

Honda models are parallel hybrid configurations – in other words, the wheels are powered by both the internal combustion engine and an electric motor.

The IMA system used in the Honda Insight features a 1.0-liter, three-cylinder VTEC-E (Variable valve Timing and lift Electronic Control) gasoline engine that produces 54-horsepower.

The ultra-thin, permanent magnet, three-phase synchronous electric motor/generator sandwiched between the engine and transmission adds 13 horsepower (10 kilowatts) as needed.

This adds up to a total of 67 horsepower, which gives sprightly, if not neck-snapping, performance.

Unlike the hybrid configurations used by Toyota and Ford, Honda’s hybrids cannot operate solely on battery power as pure electric vehicles under specific driving circumstances.

Still, Honda’s IMA fits the longstanding definition of a true integrated full hybrid, designed from the ground-up to enable vehicles to run super-efficiently on shared internal combustion and electric power.

GM Hybrid Technology

GM | Hybrid Cars, SUVs & Trucks - Hybrid Technology